function initialize() {
  var mapDiv = document.getElementById('map-canvas');
  var map = new google.maps.Map(mapDiv, {
    center: new google.maps.LatLng(41.8374949, -87.66503245),
    zoom: 11,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  });

  var ftLayer = new google.maps.FusionTablesLayer(139529);
  ftLayer.setMap(map);

  var slider = addSlider();
  slider.onchange = function() {
    ftLayer.setQuery('select * from 139529 where Age < ' + slider.value);
  };
}

function addSlider() {
  var slider = document.createElement('input');
  slider.type = 'range';
  slider.max = 70;
  slider.min = 0;
  slider.value = 70;
  document.body.appendChild(slider);
  return slider;
}
